Electric heater and venting and freezing
 

I'm building a ranch house in the high desert and I'm kicking around various schemes for heating water. In the winter at night the temperature drops to 20F. Records show the lowest was 13F. If I have any vents in the water heater closet the pipes will freeze. If I use propane then I worry the air intake will cause the water pipes to freeze. I looked at videos for installing something like a GeoSpring hybrid electric heater. Even hybrid electric heaters need vents supposedly. Do regular electric heaters need vents? I would like to create a water heater closet that is like R50 insulated and sleep at night knowing that freezing is not going to cause mayhem with my water heater. Any suggestions or thoughts on the matter?

An electric water heater needs no venting because it is not burning fuel.

I thought so much. However I noticed on the GeoSpring installation video the narrator states that 700 sq. ft. of space with louvre venting is required. So hybrid electric units apparently needs venting or access to fresh air.